Process of making lead salts.



"UNITED smrr sga rnnr OFFICE.

LOUIS S. HUGHES, 0F JDPLIiN', MISSOURI, ASSIGNOR 6F ONE-HALF T0 HIMSELF AND ONE-HALF TO PIGHER LEAD COMPANY, OF JOPLIN, MISSOURI, A CORPORATICN 0F Patented Nov. 14, 1911.

MISSOURI.

PROCESS OF MAKING LEAD SALTS.

1,008,412. Specification of Letters Patent.

No Drawing.

To all whom it may concern:

Be it h'llOWll that I, Louis S. HUGHES, a citizen of the. United States of America, residing in Joplin, in the county of Jasper, in the State of Missouri, have invented a cei'tain'new and useful Improvement in the Production of Lead Salts, of which the following is a true and exact description.

The object of the present invention is a simple. ctt'ective and relatively inexpensive method of commercially producing various lead salts, characterized on the one hand by the purity'of the salts produced, and on the other hand by the eltective use, as a lead yieldin raw material. of a by product of lead smelting and other lead and lead ore treating plants which. in the case of most of such plants. is practically a waste product.

The lead yielding: raw material which I use is the so called waste leadtor blue fume, and I prefer that given oil from open hearth lead smelting furnaces on account of its high hasieity. This t'ume is composed principally ol lead sulfid, lead sulfate,

linely divided uncousumed carbon and somelead oxid. This fume-I first subject to a strongoxidizing,- action, either by burning it in a kiln, or (as is possible in the majority ol' cases). by setting: [ire to it in a heap and allowing it to burn of itself, which it does n account of its uuconsunu-d carbon and sulfur contents. The l'ume thus'burned contains a large amount, usually orer forty per cent, oi lead oxid which behaves toward acid solvents as it it were .t'ree litharge. I then iligcst. the burned fume ilra suitable hot acid hereby the lead oxid is dissolved. The acid used may be nitric, acetic or other acid yielding soluble lead compounds.

To facilitate the digestion of the burned fume it may be broken. up when necessary into partices of suitable fineness before treatment with the acid. The liquor pro- Applioation filed June 19, 1909. Serial No. 503,046.

duced by digesting the burned fume as de seribed,,is separated frointhe subsiden residue of insoluble sulfate or other insoluble compounds preferably by decantation. This insoluble residue may be returned to the ore treating furnace or otherwise disposzd of a as may be desirable. From the decanted liquor the desired lead salts may be obtained through crystallization or precipitation by any suitable known method. Among the salts which may be produced in this manner are the following: chromate, acetate, nitrate and arsenate.

The lead salts thus made are not only produced readily at a relatively low cost but are unusually free from impurities since the tome from which they are made, being a sublimat'e. is free from the bases umally cont-animating pig lead such as bismuth, copper, (in, etc, and contains little silvery Having now described my invention, what I claim as new and desire to secure by Letters Patent is, V v

l. The method of commercially producing relatively pure lead salts from lead fum'c which consists in burning the ft me to oxidize it, treating the oxidized fume with acid to dissolve the lead oxid contained in 

